In a system for transmitting and receiving data on a moving image and the like, a protocol such as UDP (User Datagram Protocol) is used to ensure real-time transmission. Unlike protocols such as TCP (Transmission Control Protocol), this kind of protocol does not guarantee reachability of a communication packet. Accordingly, a communication packet is sometimes lost.
Refer to the following Patent Document for details on error correction of data: Japanese Patent Application Publication No. 2005-136546.
In order to correctly playback a moving image even when a communication packet is lost, it is effective to use an error correction code. For example, when transmitting a moving image in real time, a transmitter sequentially captures video images, compresses the data, and also computes an error correction code according to the compressed data. Then, the transmitter adds the error correction code to the compressed data and transmits the data.
In order to transmit data in real time, each frame of data must be transmitted within a predetermined time period. For this reason, a frame may include an image so complex that the data is compressed only at a low rate. As a result, the transmitter may not transmit the error correction code while failing to obtain the code in time. Usually, to cope with such cases, a transmission buffer is enlarged to cover the delay time occurring from computation of the error correction code. However, this increases latency inhibits real-time transmission of data. Meanwhile, if the computational time is to be reduced by using a different kind of error correction code, achieved error correction performance may not be satisfactory in some cases.